word-forming element meaning "within, inside, on the inside," from Latin preposition intra "on the inside, within, in, into;" of time, "during, in the course of," related to inter "between," from PIE *en-t(e)ro-, from root *en "in." Commonly opposed to extra-, and compare inter-. The use of intra as a prefix was rare in classical Latin.
1610s, "pertaining to the womb" (from early 15c. as "having the same birth-mother"), from Old French uterin, from Late Latin uterinus "pertaining to the womb," also "born of the same mother," from Latin uterus "womb" (see uterus).
<a href="https://www.etymonline.com/word/intra-uterine">Etymology of intra-uterine by etymonline</a>
Harper, D. (n.d.). Etymology of intra-uterine. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/intra-uterine